Simulation of Orthodontic Force of Archwire Applied to Full Dentition Using Virtual Bracket Displacement Method.

OBJECTIVE: Orthodontic force simulation of tooth provides important guidance for clinical orthodontic treatment. However, previous studies did not involve the simulation of orthodontic force of archwire applied to full dentition. This study aimed to develop a method to simulate orthodontic force of tooth produced by loading a continuous archwire to full dentition using finite element method.

METHOD: A three dimensional Tooth-Periodontal ligament-Bone Complex model of mandible was reconstructed from computed tomography images, and models of brackets and archwire were built. The simulation was completed through two steps. First, node displacements of archwire before and after loading was estimated through moving virtual brackets to drive archwire deformation. Second, the obtained node displacements were loaded to implement the loading of archwire, and orthodontic force was calculated. An orthodontic force tester (OFT) was used to measure orthodontic force in vitro for the validation.

RESULTS: After the simulation convergenced, archwire was successfully loaded to brackets, and orthodontic force of teeth were obtained. Compared to the measured orthodontic force using the OFT, the absolute difference of the simulation results ranged from 0.5 cN to 22.7 cN for force component, and ranged from 2.2 cN•mm to 80.0 cN•mm for moment component, respectively. The relative difference of the simulation results ranged from 2.5% to 11.0% for force component, and ranged from 0.6% to 14.7% for moment component, respectively.

CONCLUSIONS: The developed orthodontic force simulation method based on virtual bracket displacement can be used to simulate orthodontic force provided by archwire applied to full dentition.